a. Field of Invention
The invention relates generally to fitted coverings for mattresses, and, more particularly to an improved fitted covering having diagonally extending elastic bands at the corners thereof for holding the covering in place relative to the corners of the mattress.
b. Description of Related Art
In the art, there presently exist a variety of known fitted sheets for mattresses and the like. Such sheets typically employ an elastic binding at the lower edge of the sheets. For certain sheet designs, additional widthwise or diagonally extending elastic bands may be provided at the corners of the sheet. The elastic binding in conjunction with the elastic bands facilitates fitting of the sheet on mattresses of different sizes, and further eliminates wrinkles in the fitted sheet.
Although the elastic binding and elastic bands provide adequate retention onto a mattress, one drawback of existing band designs is that when a sheet is grasped to lift up the underlying mattress, significant forces may be applied to the diagonal bands at the corners of such sheets. If a sheet is primarily used to lift up an underlying mattress, the elastic bands may pull away from the sheet at the point of attachment, particularly since these elastic bands are quite strong and are not usually subject to tearing at an intermediate point thereof.
Therefore, an important consideration in the construction of such fitted sheets is to provide an economical and strong manner of attaching the corner elastic bands thereof to the lower edge portions of the sheet, which will ensure that the durability of the bands in use is based on the strength of the bands themselves and not on the strength of the interconnection between the bands and the sheet.
A known fitted sheet invented by the inventor of the fitted sheet disclosed herein is described in U.S. Pat. No. 5,513,403 ('403 patent), the disclosure of which is incorporated herein by reference. Referring to FIGS. 1 and 8 of the '403 patent, the fitted sheet disclosed in the '403 patent includes fitted sheet 20 mounted on a conventional rectangular mattress 10 having a bottom face 12 and an opposite upper face 14. Sheet 20 includes a top portion 22, opposite side portions 24 and opposite end portions 26. The side and end portions of sheet 20 have lower edge portions which terminate in lower edges, and as seen in FIGS. 2 and 3, each side portion 24 has a lower portion 24′ which terminates in a lower edge 24″.
As shown in FIGS. 2-4 of the '403 patent, an elastic binding 40 is formed of conventional material and is disposed around the continuous lower edge of sheet 20 and extends along the entire length of the lower edge of the sheet. Binding 40 further includes an inwardly facing surface 44 and an outwardly facing surface 46. Sheet 20 further includes four similar elastic bands 50, each of these bands extending diagonally across one of the corners of the sheet. As shown in FIG. 6, each band has one end thereof secured to one of the side portions of sheet 20 and the opposite end thereof secured to an adjacent end portion of the sheet.
Referring to FIG. 2, in order to secure an end of band 50 to a side portion of the sheet, the end 50′ of band 50 is initially sandwiched between the inwardly facing surface of side portion 24 and binding 40, and is secured in place by the line of stitching 42. Each band 50 thus terminates in an end edge 50″ which is disposed adjacent to the lower edge 241 of side portion 24. In order to ensure that the end of band 50 will not pull away from the sheet, a supplementary securing means in the form of a bar tack 54 is provided. Specifically, as shown in FIG. 3, the end of each band 50 is secured to the sheet by folding band 50 over the upper edge of binding 40 and then positioning it against the inwardly facing surface 44 of the binding. Bar tack 54 extends through the associated lower edge portion of side portion 24, through two layers of binding lying on opposite sides of the lower edge portion of side portion 24, and through two layers of band 50 lying on opposite sides of the inner part of the binding.
Based upon the construction discussed above, if sheet 20 is primarily used to lift up the underlying mattress, elastic band 50 will separate at an intermediate point and be destroyed before the ends of the band will tear away from the sheet.
Although the fitted sheet construction described in the '403 patent has adequate strength at the connection points of the diagonal elastic bands for most operations, in certain situations and during certain abnormal use, elastic band 50 may be yanked loose from the fitted sheet and thus tear the sheet at the connection point. For certain manufacturing requirements, the fitted sheet construction described in the '403 patent may be economically prohibitive to manufacture. Additionally, for certain fit and finish requirements, the fitted sheet construction described in the '403 patent may have an insufficient wrinkle-free fit and finish.
There thus remains a need for an improved fitted sheet having diagonally extending elastic bands at the corners thereof, with the elastic bands being connected by an improved connection method so that the bands remain connected to the sheet despite being subjected to abnormal use. Moreover, compared to the elastic bands and connection techniques disclosed in the '403 patent, there also remains a need for an improved fitted sheet having diagonally extending elastic bands which are simpler to connect and utilize less raw material, and the fitted sheets are simpler and more economical to manufacture, and are ergonomically superior to those of the '403 patent.